Http probelm

[semerouk]

Dear all
I'm using ZCS 6 open source
i have something unexpected

When i'm trying to access my web mail i found the following message :

The connection has timed out
The server at mail.xxxxxxxxxx.org is taking too long to respond.
* The site could be temporarily unavailable or too busy. Try again in a few
moments.
* If you are unable to load any pages, check your computer's network
connection.
* If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.
and when i'm trying to ping my mail server it didn't response.
that's happens from any computer.

On my zimbra server
every thing looks fine .

Any one can help me please .

Thanks